LeastSquareEllipse2dSee full documentation

least square ellipse associated to shape tops

This measure allows to compute least square ellipse associated to each shape.

Given a shape, algorithm will compute a least square ellipse approximation of shape tops :

Estimated ellipse can be computed using a simple parametric estimation of shape tops or can be computed using a robust estimation technic. This behavior is ruled by measure parameter, see ipsdk::imaproc::attr::RobustEstimationConfig.

For more information on parametric estimation process (including outliers management) please reports to Parametric estimation.

Here is an example of the least square ellipse computation on a grey scale image:

least square ellipse associated to shape tops

Measure synthesis :

Measure Type	Measure Unit Type	Parameter Type	Result Type	Shape Requirements
Geometry 2d	None	LeastSquareEllipse2dMsrParams	Custom	Boundary Approximation

See Shape measurement for additional information on these pictograms

Example of Python code :

Generic example in 2d case :

import PyIPSDK
import PyIPSDK.IPSDKIPLShapeAnalysis as shapeanalysis

    # Create the infoset
    inMeasureInfoSet2d = PyIPSDK.createMeasureInfoSet2d()
    PyIPSDK.createMeasureInfo(inMeasureInfoSet2d, "LeastSquareEllipse2dMsr")
    
    #Perform the analysis
    outMeasureSet = shapeanalysis.labelAnalysis2d(inGreyImg, inLabelImg2d, inMeasureInfoSet2d)
    
    # save results to csv format
    PyIPSDK.saveCsvMeasureFile(os.path.join(tmpPath,  "shape_analysis_results.csv"), outMeasureSet)
    
    # retrieve measure results
    outMsr = outMeasureSet.getMeasure("LeastSquareEllipse2dMsr")
    
    # retrieve measure values
    outMsrValues = outMsr.getMeasureResult().getColl(0)
    print("First label estimation orientation : " + str(outMsrValues[1].first.getOrientation()))
    print("First label estimation center : " + str(outMsrValues[1].first.centerX()) + ", " + str(outMsrValues[1].first.centerY()))
    print("First label estimation major radius : " + str(outMsrValues[1].first.getMajorRadius()))
    print("First label estimation minor radius : " + str(outMsrValues[1].first.getMinorRadius()))

Example of C++ code :

Example informations

Associated library

IPSDKIPLShapeAnalysis

Code Example

    // opening grey level input image
    ImagePtr pInGreyImg2d = loadTiffImageFile(inputGreyImgPath);

    // read entity shape 2d collection used for processing
    Shape2dCollPtr pShape2dColl = boost::make_shared<Shape2dColl>();
    IPSDK_REQUIRE(readFromXmlFile(inputShape2dCollPath, *pShape2dColl) == true);

    // define a measure info set
    MeasureInfoSetPtr pMeasureInfoSet = MeasureInfoSet::create2dInstance();
    createMeasureInfo(pMeasureInfoSet, "LeastSquareEllipse2dMsr");
    
    // compute measure on shape 2d collection
    MeasureSetPtr pOutMeasureSet = shapeAnalysis2d(pInGreyImg2d, pShape2dColl, pMeasureInfoSet);

    // retrieve associated results
    const MeasureConstPtr& pLeastSquareEllipse2dOutMsr = pOutMeasureSet->getMeasure("LeastSquareEllipse2dMsr");
    const LeastSquareEllipse2dMsrResults& outResults = static_cast<const LeastSquareEllipse2dMsrResults&>(pLeastSquareEllipse2dOutMsr->getMeasureResult());